In a mobile communication system, two typical entities exist for saving user data, one is a home location register (HLR, Home Location Register) of a user equipment (UE, User Equipment), and the other one is a visitor location register (VLR, visitor location register) of the UE. The HLR manages information about a subscribed mobile user, all user data is stored in the HLR, and an address of a VLR currently visited by the UE is recorded in the user data. The VLR stores information for calling or other purposes of a mobile user visiting the VLR, and the information records an address of a location area that the UE resides. The user data in the HLR is static and permanent in a user survival period, while user data in the VLR is dynamic and exists only when the UE roams in the VLR. Lost user data in the VLR may be re-obtained from the HLR through a location update or data recovery.
During the implementation of the present invention, the inventors find:
In a case, after the VLR is reset due to a VLR upgrade, restarting caused by a fault, or another reason, registration of the user needs to be performed, that is, the VLR sends a location update request message to the HLR; or as for a machine user, when power supply is restored after mains power-off, a great number of machine users may be restarted and location updates may be initiated in batch. If a great number of registrations are performed in the VLR at the same time, message traffic at a D interface between the VLR and the HLR jumps sharply, and message congestion and a system breakdown easily occur.
In another case, when the HLR is overloaded, the HLR refuses a location update service; however, since the location update of the UE is automatically performed by a terminal, the terminal may make repeated retries till the location update is successful when the location update fails. In an existing network, it is found through actual detection that, a part of terminals may make repeated retries after a failure till the location update is successful, so the HLR fails to achieve an objective of reducing traffic through refusing the location update request message, which may lead to a higher load, a worsened condition or even the system breakdown.